1. Field of Invention
The invention relates to a main-board and a control method thereof and, in particular, to a main-board and a control method thereof capable of enabling a memory module to achieve a higher and more efficient information-transmitting frequency without being restricted by a fixed transmission frequency ratio of a chipset.
2. Related Art
With the progress of the computer technology, the memory with a higher clock also has been successfully developed. The memory that is mostly widely used in the market is the DDR (Double Data Rate) memory, which is the mainstream standard of the PC memory in the past few years. The current DDR specification has reached 400 MHz, but another memory with the DDR2 specification is ready to replace the current DDR memory. The DDR2 specification starts from 533 MHz and is developed toward 667 MHz. The higher clock can achieve the higher data transmission efficiency and enhance the computer efficiency. Meanwhile, the DDR2 memory is more power-saving. According to the statistical result of Samsung Company, the power consumption of the DDR2 memory of 533 MHz clock is smaller than 65% that of the DDR memory of 400 MHz. This also can save the power consumption of the notebook computer. However, the available chipsets on the main-boards have been set some preset specification ratio. Regarding to the CPU (Central Processing Unit) having a specification of FSB-800, for example, the corresponding memory should be a maximum specification of DDR2-533 according to the preset specification ratio set in the chipset.
Referring to FIG. 1, a conventional main-board includes a CPU 11, a chipset 12, a memory module 13 and a clock-generating module 14. The clock-generating module 14 generates a clock signal CK0, which is inputted to the CPU 11 and the chipset 12. The CPU 11 provides ratio information to the chipset 12, wherein the ratio information I0 is a specification ratio that is originally set in the chipset 12. For example, if the specification ratio is 2:3, the corresponding CPU 11 and memory module 13 may respectively have the specifications of FSB-533 (CPU-bus 133 MHz) and DDR2-400 (Memory-bus 200 MHz). Furthermore, if the specification ratio is 5:6, the corresponding CPU 11 and memory module 13 may respectively have the specifications of FSB-667 (CPU-bus 166 MHz) and DDR2-400 (Memory-bus 200 MHz).
As mentioned above, because the chipset always has some preset and fixed specification ratios, the efficiency of the memory module with a higher clock is restricted, and the data transmission efficiency set in the memory module itself cannot be achieved. Therefore, it is an important subjective to provide a main-board capable of making the memory module achieve the information-transmitting frequency with higher efficiency without being restricted by the fixed specification ratio that is set in the chipset.